Vegan gardeners have recently begun worrying about the animal products in their plant foods.  Almost all fertilizers are animal product based.  A Humboldt Co.  is offering an entire product line that has no animal by products in it. According to a press release in the SF Gate,

Humboldt Plant Fertilizers (HPF) is breaking new ground by becoming the only natural liquid plant nutrient company banning any use of slaughterhouse by-products such as the bone meal, blood meal, and feather meal almost universally found in all other natural fertilizer products.

Every product manufactured by HPF now bears the “Holy Cow” symbol, which clearly states the pledge to never use animal by-products. The other major nutrient lines may have single amendments, but not a stand alone system of natural nutrients for vegetarians to grow medicinal marijuana.